Preparation of 1M Magnesium Chloride (MgCl2) Stock Solution


Magnesium Chloride (MgCl2) is soluble in water. Magnesium chloride is available in anhydrous as well as hydrated forms. Since anhydrous Magnesium chloride is hygroscopic (quickly absorbs water from the air), it is convenient to use hydrated forms that are easy to weigh out the right amount accurately. For this reason, Magnesium chloride hexahydrate (MgCl2.​6H2O, Molecular Weight: 203.30) is often used to prepare a 1 M Magnesium chloride solution.

A 1M stock solution can be prepared by dissolving 203.3 g of  MgCl2.​6H2O (Molecular Weight: 203.30) in water to a final volume of 100 ml. 

In the following section, we describe a procedure to prepare 100 ml of 1M MgCl2 stock solution.

Preparation of 1M Magnesium Chloride (MgCl2) Solution from MgCl2.6H2O


Reagents and solutions
Magnesium chloride (MgCl2.​6H2O) (Molecular Weight: 203.3)
Deionized / Distilled water / MilliQ water

Equipment and disposables
Measuring cylinder
Conical flask / Beaker
Magnetic stirrer (optional)

1 M Magnesium chloride

Preparation of 100 ml 1 M Magnesium chloride


Use appropriate personal protective equipment (lab coat, gloves, goggles, etc) for your safety and follow the guidelines of your institute.

Step 1: To prepare 100 ml of 1 M Magnesium chloride, weigh out 20.33 g MgCl2.​6H2O (Molecular Weight: 203.30) in a 250 ml conical flask/beaker. Add 80 ml deionized/Milli-Q water and mix it. 

One can use manual shaking using a glass pipette to mix the ingredients. Magnetic stirrer makes the dissolving process easy and convenient.

Do not dissolve in 100 ml of deionized / Milli-Q water. In most cases, solution volume increases when a large amount of solute is dissolved in a solvent.

Step 2: Adjust the volume to 100 ml with deionized / Milli-Q water. Mix it again.

Step 3: Sterilize the solution by autoclaving (20 minutes at 15 lb/ (psi) from 121-124°C on liquid cycle).

The solution can also be sterilized by filtering through a filter unit containing a membrane with a pore size of 0.22 µm or less under sterile conditions.

The solution can be stored in a cold room or at -20°C.

Magnesium chloride solution is not very stable. Freezing stock solution at -20°C in small aliquots is recommended (Bunce & Passey, 2013).

Follow the table to prepare Magnesium chloride of various concentrations and volumes (10, 100 ml, 500 ml, 1,000 ml, and 10,000 ml).
Solution concentration / Volume10 ml100 ml500 ml1000 ml
0.1 M0.2033 g2.033 g10.165 g20.33 g
0.5 M1.0165 g10.165 g50.825 g101.65 g
1 M2.033 g20.33 g101.65 g203.30 g


Was this post helpful?

Author: admin

Leave a Reply

Your email address will not be published. Required fields are marked *